In recent years, DVD (Digital Versatile Disc)-Videos having greatly increased storage capacities are coming into wide use in place of conventional laser discs and video CDs, and many movies are put on the market. These DVD-Video standard discs are standardized attaching importance to playback of video, without attaching importance to playback of various types of audio. Therefore, DVD-Video standard cannot realize playback in conditions of linear PCM, 192-KHz sampling frequency, 24 bit/sec, 2 channels, and more than 74 minutes, or playback in conditions of linear PCM, 96-KHz sampling frequency, 24 bit/sec, 6 channels, and more than 74 minutes, for example. Accordingly, DVD-Audio standard is established as DVD standard which attaches importance to the playback of various types of audio. As shown in FIG. 6 showing the relationship on standards between DVD-Video standard and DVD-Audio standard, the physical layer structure and file layer structure of DVD-Audio standard are the same as those of DVD-Video standard, and only its application layer structure is different from that of DVD-Video standard. However, DVD-Video standard and DVD-Audio standard have a common part in the application layer structure. FIG. 7 shows the comparison of contents between DVD-Video standard and DVD-Audio standard. (Note: DVD-Video standard Ver.1.0, issued in August 1996, DVD-Audio standard Ver.1.0, issued in March 1999.)
A data structure according to DVD standard is divided broadly into a Volume zone and a File zone. Information of files in the File zone is recorded in the Volume zone. Video data files, audio data files and files of data other than audio/video data (for example, computer data) are recorded in the File zone. The video data files, the audio data files and the files of data other than audio/video data correspond to a DVD-Video zone, a DVD-Audio zone and a DVD-others zone, respectively.
FIG. 8 shows a data structure of a file in a DVD-Video standard disc. Three zones, i.e., a DVD-Volume zone 81, a DVD-Video zone 82 and a DVD-Others zone 83 are defined. Among those, the DVD-Video zone 82 comprises one piece of video disc management information (i.e., Video Manager, hereinafter referred to also as “VMG”) 84 and one or more Video Title Sets (hereinafter referred to also as “VTS”) 85.
On the other hand, FIG. 9 shows a data structure of a file in a DVD-Audio standard disc having both of an Audio zone and a Video zone. Four zones, i.e., a DVD-Volume zone 91, a DVD-Audio zone 92, a DVD-Video zone 93 and a DVD-Others zone 94 are defined. Among those, the DVD-Audio zone 92 comprises one piece of audio disc management information (i.e., Audio Manager, hereinafter referred to also as “AMG”) 95 and one or more Audio Title Sets (hereinafter referred to also as “ATS”) 96. The DVD-Video zone 93 comprises one VMG 97 and one or more VTSs 98. That is, according to DVD-Audio standard, one disc can simultaneously have the DVD-Audio zone 92 and the DVD-Video zone 93. When titles in the DVD-Audio zone 92 are to be selected, the ATS(#1-#m) 96 are selected and when titles in the DVD-Video zone 93 are to be selected, the VTS(#1-#n) 98 are selected. Although the DVD-Video zone 93 has the VMG 97, when the disc is to be managed as a DVD-Audio standard disc, the whole disc is managed using the AMG 95 instead of the VMG 97. When this disc is to be managed as a DVD-Video standard disc, the whole disc is managed using the VMG 97 instead of the AMG 95 while the Audio zone 92 cannot be played back.
FIG. 10 shows a data structure of a file in a DVD-Audio standard disc having only an Audio zone. In this case, since there is no Video zone, no VMG is included and only the AMG is included as disc management information.
FIG. 5 shows a case where the DVD-Audio standard disc including both of the ATSs and VTSs as shown in FIG. 9 is played back using the AMG, and FIG. 4 shows a case this disc is played back using the VMG. When the disc is played back using an AMG 60 as shown in FIG. 5, whether a selected title is the ATS or VTS is included in a Title Set Search Pointer 66 in the AMG 60 as Audio Title Category information 67.
As shown in FIG. 5, Title Set Management Information 68 includes Object Position Information 75 indicating the position of audio/video data on the optical disc and Sequence information 76 indicating the playback order of the audio/video data in a lower layer, as Program Chain Information (hereinafter referred to also as “PGCI”). When the playback is to be performed, a Title Set which is specified by the PGCI in the Title Set Management Information is played back. Conversely, even when there are audio/video data as Title Sets, when the playback order indicating the data is not specified by the PGCI, the data are not played back. When the disc is played back using the VMG 40 as shown in FIG. 4, Title Set Search Pointers 45 included in the VMG 40 have no information indicating the ATS but all of those indicate the VTS 41. Therefore, titles which are selected are only VTSs.
There are three kinds of DVD discs depending on the disc management information, i.e., DVD-Video standard discs having only the disc management information of VMG, DVD-Audio standard discs having only the disc management information of AMG, and DVD-Audio standard discs having both of the disc management information of VMG and AMG. In the flu DVD-Video standard discs, the playback is performed according to the disc management information of VMG. The DVD-Audio standard discs may include both of the disc management information of AMG and VMG. However, when the discs are played, the playback is performed using one of the disc management information according to types of players. At this time, when the VMG is employed, only the VTSs are managed. When the AMG is employed, the ATSs and VTSs are managed. However, since part of region code management or navigation commands which are specified by the VMG are not defined by the AMG, the whole VTSs are not always managed by the disc management information of AMG. That is, the number #n of VTSs which are managed by the AMG as shown in FIG. 5 is equal to or smaller than the number #p of VTSs which are managed by the VMG as shown in FIG. 4.
FIG. 11 shows the relationship between the discs and players in considering the playback method being combined with the players. To be specific, when a DVD-Video standard disc 112 having only VTSs is played back by a conventional DVD-Video player 111, all the VTSs are played back according to the VMG disc management information. When a DVD-Audio standard disc 114 in which ATSs and VTSs are mixed and which has both of AMG and VMG is played back by the DVD-Video player 111, the playback is performed similarly according to the VMG disc management information, whereby all the VTSs are played back, but the ATSs are not played back. On the other hand, when the DVD-Audio standard disc 114 having both of the AMG and VMG is played back by a DVD-Universal player 113, the playback is performed according to the AMG disc management information, whereby part of the ATSs and VTSs are played back. This relationship is shown in FIG. 12.
Even when the DVD-Universal player 113 which can play back all of the DVD-Video standard disc 112, a DVD-Audio standard disc 116 and the DVD-Audio standard disc 114 having the ATS and VTS mixed is designed, the player 113 is defined so as to play back titles by using the VMG for the DVD-Video standard disc 112 and the AMG for the DVD-Audio standard discs 114 and 116. Therefore, while all the VTSs in the disc 112 can be played back using the VMG and all the ATSs in the disc 116 can be played back by using the AMG, only part of the ATSs and VTSs are played back when the disc 114 is played back using the AMG, and there is a risk of not all the VTSs being played back.
That is, even in the case of the DVD-Universal player, some VTSs cannot be played back in some discs. In this universal optical disc playback apparatus, it is required to play back all the ATSs and VTSs even when the DVD-Audio standard discs including both of the VMG and AMG are played back.